Digital wireless network standards such as Bluetooth or DECT or proprietary systems often include a security measure to ensure that two devices that are in operative reach of each other are mutually accepted. This procedure is termed pairing and may involve the exchange of a passkey, typically involving user input. Normally, when two Bluetooth devices are to be paired, one or more buttons on each device have to be pressed for a certain amount of time to bring the devices into a mode where pairing can occur. For elderly people or other people with limited technical skills, this may be a complicated task, which can ultimately limit the success of devices (e.g. digital wireless hearing aid accessories) based on the Bluetooth technology. In the Bluetooth 2.1 specification a so-called touch to pair feature based on near field communication according to the NFC standard is introduced.
US 2009/0058608 describes a method for connecting wireless electric actuating devices to a medical appliance via a wireless communication channel. The method comprises the steps of initiating the connection operation for a wireless electric actuating device to a medical appliance and performing a connection procedure, in which the actuating device is assigned to the medical appliance. The initiation of the connection operation is carried out from the medical appliance, e.g. via a push button.
WO 2005/109781 A1 describes a method of pairing a first electronic device and a second electronic device in a radio communications system, comprising the steps of: bringing the first and second electronic devices in proximity to each other; transmitting an inquiry signal from said second electronic device; transmitting an inquiry response signal from said first electronic device, upon detecting said inquiry signal; initiating point-to-point connection between said first electronic device and said second electronic device, based on said first electronic device being the first device to respond to said inquiry signal. Preferably, said inquiry signal has an output power restricted to a first power level, which first power level is lower than a standard signal power level in said radio communications system.
US 2003/0050009 A1 deals with a Bluetooth device wherein the output RF transmission power level during pairing is purposefully reduced from otherwise conventional or normal communication levels to a low power level, greatly reducing the range of possible interception.